Bothriochloa ischaemum (L.) Keng

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Graminae

Synonyms

Andropogon ischaemum (L.).

Common names

Plains blue-stem, King Ranch blue-stem, Turkistan blue-stem, yellow blue-stem (United States).

Description

It is a warm-season perennial bunch grass, sometimes forming a sod. It grows to 0.3-0.5 m with creeping root-stock, erect culms, simple or sparingly branched above, glabrous or pubescent at nodes. Leaves glaucous, hairy at base. Three to ten digitate spikes, linear, 4-6 cm long, greyish.

Distribution

Afghanistan, India, Iraq, Pakistan, USSR, Turkey, south-western United States (Oklahoma, Texas, Kansas, Missouri, Arkansas).

Rainfall requirements

It is adapted to 375-1 000 mm rainfall.

Drought tolerance

It is drought resistant.

Soil requirements

'Plains Blue-stem' is adapted to a wide range of soils from well- drained good sandy soils to loam and clay loam soils, but not to deep sands. It has some tolerance to soils which produce iron chlorosis. It prefers limestone soils.

Ability to spread naturally

It volunteers readily from seed.

Land preparation for establishment

A good, clean, firm seed-bed is needed.

Sowing methods

The fluffy seed is mixed with fertilizer and sown through a drill or fertilizer spreader using a coarsely ground fertilizer.

Sowing depth and cover

Sow on surface and roll or cover lightly.

Sowing time and rate

Sow in the early summer at 11-17 kg/ha.

Number of seeds per kg.

3.1 million.

Seed treatment before planting

The seed requires hammer-milling before planting.

Seedling vigour

Excellent.

Vigour of growth and growth rhythm

It has a growth similar to Bermuda grass (Cynodon dactylon) in Oklahoma. It can be grazed throughout the winter there. It grows well in late summer and autumn in the United States, flowering from June to October.

Dry-matter and green-matter yields

The average annual yield of green matter on a black day soil in Maharashtra State, India, with light irrigation during the hot months December to May was 8 724 kg/ha from three cuts each for three years and four cuts one year (Whyte, 1964). In Oklahoma, United States, yields of dry matter per hectare were 3 288 kg with no nitrogen fertilizer, 6 545 kg with 110 kg N/ha, and 10 039 kg with 220 kg N/ha (Dalrymple, 1978). In a seven-year study at the Noble Foundation, Oklahoma, it outyielded Bermuda grass cv. Midland by 23 percent. In Gujarat, India, it yielded 15 680 kg/ ha green matter ­ better than C. ciliaris, Dichanthium annulatum, Eragrostis superba, Panicum antidotale and P. repens.

Suitability for hay and silage

It has made good hay in the United Republic of Tanzania and in the drier zones of Hawaii.

Toxicity

No toxicity has been reported with this grass.

Cultivars

  • 'Plains Blue-stem' 
a blend of morphologically similar selections of the same pasture species. The selections come from Afghanistan, India, Iraq, Pakistan, the USSR and Turkey.
  • 'King Ranch Blue-stem' 
has been used for several decades in the United States. It is a high-quality grass that can produce greater yields than native grass, but less than 'Plains' and 'Caucasian' blue-stems. It can be used well as a range grass but as there are more productive grasses, very little 'King Ranch Blue-stem' is planted today. It can form a sod almost as dense as Bermuda grass and can be used for erosion control.
  • 'Elkan Blue-stem' 
more cold resistant than other strains.

Main attributes

Its winter hardiness and palatability.

Palatability

'Plains Blue-stem' is quite palatable and leafy, but is extremely prostrate in Kenya.

Chemical analysis and digestibility

Advanced plains blue-stem with stemmy growth gave an average digestibility of 48.6 percent. The crude protein content averaged 4.7 percent during the winter of 1978 with a phosphorus content of 0.08 percent (Dalrymple, 1978).

Natural habitat

Dry stony places, borders of fields and slopes.

Tolerance to flooding

It has no tolerance to flooding.

Fertilizer requirements

In the United States a planting mixture of NPK (1620-0, 18- 46-0 or 10-20-40) is used. It responds well to fertilizer, but gives good quality forage at low fertility rates. A yield of 30 kg of dry gross can be expected for every kilogram of nitrogen.

Genetics and reproduction

2n=40, 50, 60. It is a pseudogamous apomict.

Animal production

Newly purchased 159 kg steers gained 0.45 kg per day grazing 'Plains Blue-stem' during late summer and autumn in Oklahoma. Weaner calves gained 0.66 kg per day for the first 35 days and 0.24 kg/day for the last 34 days for an overall daily gain of 0.45 kg per head per day for 69 days (Dalrymple, 1978).

Further reading

Dalrymple, 1978; Harlan et al., 1961.

Dormancy

There is some post-harvest dormancy.

Value for erosion control

Valuable for reseeding eroded soils in the central and southern Great Plains of the United States. It was found to be one of the most effective soil stabilizers to maintain the bunds in the ravine lands of Gujarat, India, with an elaborate root system and excellent ground cover (Srinivasan, Bonde & Tejwani, 1962).

Tolerance to salinity

'King Ranch Blue-stem' has some salt tolerance.